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# trigonemtry using CAST method Watch

1. hey need help, does anyone know how to solve cos3x = 0.5 using the cast method? I only know how to solve for x from ranges 0 - 360 so only pick up like 2 /4 marks in these type of questions, but does any one how to solve for x above 360 degrees ??????
2. (Original post by trianglelifx)
hey need help, does anyone know how to solve cos3x = 0.5 using the cast method? I only know how to solve for x from ranges 0 - 360 so only pick up like 2 /4 marks in these type of questions, but does any one how to solve for x above 360 degrees ??????
Add 360 and 720 (or 2 pi and 4pi if it's radians) to the two answers you got for cos^-1 (0.5)

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3. (Original post by gdunne42)
Add 360 and 720 (or 2 pi and 4pi if it's radians) to the two answers you got for cos^-1 (0.5)

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Thanks!

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